Nucleation rate surface topologies for binary systems

Recent experiments have found that two nucleation rate surfaces can be obse rved for two different critical embryo phases (solid and liquid) near the t riple point of the condensing species. Direct experimental evidence was pre sented of the existence of two independent nucleation rate surfaces with on e of them existed over metastable vapor-liquid-phase equilibrium lines. The se results force more careful consideration of the role of metastable phase equilibria in the topology of nucleation rate surfaces. In the present stu dy, the topology of the nucleation rate surface for a binary vapor in which partial solubility of the condensed components is considered. Schematic mu ltiple surfaces over the phase diagram with a eutectic point, presenting tw o-channel nucleation, are constructed. Vapor-liquid nucleation in a carrier gas in most cases is a binary system with partial solubility of condensate . It is reasonable to propose that multiple nucleation rate surfaces are co mmon phenomena for many systems. Sulfur hexafluoride-n-pentanol nucleation was experimentally studied using a flow diffusion chamber. The experimental results for n-pentanol-sulfur hexafluoride at total pressures of 0.10, 0.2 0, and 0.30 MPa are presented. All experimental conditions were recalculate d to correspond to a nucleation temperature of 255.0 K. The observed convol uted lines of In J plotted against In S provide experimental evidence of th e existence of multiple nucleation rate surfaces. It can be anticipated tha t a variety of multiple nucleation rate surfaces, such as presented here, w ill be detected soon. Obviously, the application of one-component nucleatio n theory for such systems with multiple nucleation rate surfaces will not b e consistent with the data. Separation of the multiple nucleation surfaces reduces the problem to a simpler one-channel treatment of nucleation. It wi ll then be possible to construct a consistent nucleation theory for a given series of compounds.